Apparatus for undercutting pinholes in the center shells of insulators



July 17, 1928. w. H. SMITH APPARATUS FOR UNDERCUTTING PIN HOLES IN THE CENTER SHELLS QF INSULATORS Filed Jan. 11, 1927 Patented July 17, 1928.

onian-n sraras WmWm 1 WILLIAM HENRY SMITH, OF "NORRI STOWN, PENNSYLVANIA, ASSIGNOBQ BY ASSIGNMENTS, TO ELECTRIC SERVICE SUPPLIES COMPANY, OF PHILADELPHIA,

PENNSYLVANIA, A conPonnrro or rnNNsYLv ANrA APPARATUS Non uNDnRoIiT'rING rI no Es IN THE C ENTER sHnLLs or INsuLA'rdRs.

Application fi led iaaua'iy n; 1927., seriarnofieasos.

My invention relates to mechanism for use in connection, with the production of insula tors and more particularly for use in undercutting the center pinhole formed in the center shell of insulators of the suspension WP? a a As is well known, insulators and more particularly insulators of the suspension type, include as an element'a center shell of non- 10 conducting material, usually porcelain. "The center shell is formed with an apron and a head portion over which fits and to which is adapted to be secured a cap, usually of metal and provided witlrmeans enabling it to be secured to a support- The head portion is provided with a pinhole or other insulator, within which a pin, adapted to be connected with a cable clamp, isgsecu-red. In the'usual construction, the pinis secured within the 1926, Serial No. 158,7 57, and my presentim' vention will bedescribed more particularly in connection with an embodiment for'undercutting the pin hole and formingatapered surface such as is provided in the Osborn insulator, though it will be understood that I do not intend thatmy invention shall be limited to the formation of 'anyiparticular undercut, since the mechanism embodying myinvention may be utilized for the formation of various forms of undercuts and grooves within the pin hole without departing from the essence of my invention.

the nature and purpose of my invention I will proceed to a detailed description thereof with reference to the accompanying drawing in which isillustrated a preferred embodiment and in which:

Figurel isa sectional View partly broken away of a device embodying my invention, a

Having now indicated in aigeneral way cutting tool thereof being" illustrated as turned out of normal position to show the cutting portion thereof.

Figure 2 is a fragmentary view partly in section showing a detail-of construction of the device illustrated in Figure l. b

Figure 3is detail view partly in section showing a cutting tool and support therefor 1n the same position as in'Fig. 1. A

F igure 1 is sectional View taken on line 4-4:, Figure 3. p

Inthe drawings a indicates' a bench or table supported by legs or supports I), while 0 indicates a post or upright member sup ported from table a and connected to a similar post or upright by means of cross meld bers d. A Yvertical shaft e extends upwardly through the table'm'between; the posts. (2.

At a point beneath the table the shaft e is provided with a pulley for'the reception of a driven belt by which the shaft may be ro- 'tated and has. secured to itsii'pper enthabove thetable, a cup f for the reception of a'mo'ld g,w 1th1n which is the center shell h of an in sulator.

The center shell as formed inthe mold g is providedwith a cylindrical pin hole indicated by the dotted line 2', Figure 1, As will benoted, if desired the'cup X may be formed to receive the center shell: directly if it has been previously removed from the mold and further,'it will be noted that if the shaft 6 be rotated the Center shell 'willbe rotated Entending verticallythrough apertures in the cross members cl is a rod 9' the upper end of which is connected to counter weight/ a, through the medium of a cordZ, which passes over a pulley m, ona shaft 72, sup-v ported by posts 0.: The counter weight lifts the rod j w position determined by the engagement of a stop 0, on the rodgwith'the underside of the uppercross member (Z.

The lower end of the rod j is reduced and threaded for the reception of 01 1 head p ,having a reduced threaded portion upon which'is threaded the shank of a cutting tool 9. The cutting tool g iscurved-an djpreferably semicircular in cross section,though it maybe more or lessthan semicircular and is provided with an enlargedtapering head g having a closed end 7? and having a cutting edge 8. Adjacent the edge of the tool opposite to the cutting edge is formed .an internal rib or bead t, which extends for a. distance along the edge of closed end 1'. A

handle it isprovided on the rod 7' adjacent tool head-p.

"The aperture v m the lower cross member V (I through which the rod j passes is made in one direction substantially larger than the duction of the undercut indicated at Figure 'ro'dand' the aperture in the upper cross member receives the rod loosely so thatthe rod and the tool supported thereby may be moved laterally av distance fixed b an adjustable stop w projecting into t e aperture 11., I

When the rod j is in normal position, the tool 9, which is made of a size to freely enter the pin hole in the center shell as formed by molding, ispositioned above vand inline with the pin hole, as indicated by the extensions of the dotted lines 2', Figure 1. 1

To 'efl'ect the" undercutting of a center shell h supported, as indicated, androtated,

by rotation of shaft 6, the tool is entered in the pin hole until its closed end 1" bears on the bottom of the pin hole. The tool is then gradually moved laterally out of center into the hole causing the cutting edge of its head 9 to cut in the wall. The tool is moved laterally until stopped by the engagement of rod j with stop w which results in the pro- 1. It is to be understood that the tool 9, for clarity, is shown asrotated on its own axis in Figs. 1, 3 and 4:. It is clear that in operation that the cutting edge 8 is positioned so.

that it is caused to cut when the rod j is moved laterally, that is, it is placed forward- 7 1y of the general direction of lateral rod movement during cutting. 7

During the operation the shaving taken oil by the cutting edge is guided and caused to be-retained-within the body of the tool by the rib t sothat the shaving may be removed 7 from the hole with the tool. The closed end 1' of the tool serves to smooth or iron the bottom of the pin hole and the edge opposite the cuttin edge serves to smooth or iron the wall I of tiie hole during the cutting operation.

After the undercut y is completed'the tool may be readily removed fromthe hole by merely moving it laterally to normal position centrally of the hole and raising it.

It will be obvious thatif it be desired to 7 form grooves within the pin hole or form it the production of a smooth finished surface. 7

Having now fully described my invention, what I claim and desire'to protect by Letters Patent is:

1. In apparatus for undercutting the pin holes of center shells forinsulators, in com bination, asupport for a center shell and a. cutting tool supported for vertical and transverse movement relative to said support, and means associated with said" tool for preventing the material removed from interfering with "the cutting edge of said tool. a

2. Inapparatus tor undercutting the pin holes of center shells for insulators, incombmatlon, a support tor a center shell, a cutting tool supported coaxially witlrthe axis of said support and adapted for'movement vertically and transversely relative its axis, and means associated with said toolfor preventing the material removed from in' terfering with the cutting edge ofsaid tool.. 1

' 3. In apparatus for undercutting the pin holes of centershells for insulators, in combination, a rotatable supportpfor a center shell, a cutting toolsupported coaxia-ll y with the axis of said support and adapted for r movement vertically and transverselyrelative its axis, said tool having a hollow form With one cutting edge and another ribbed edge, whereby material being cut is prevented from interferingwith the cuttingedgeof said tool and whereby said material may be removed when said tool is removed.

' 4i. A tool for undercutting the pin holes of center shells for insulators comprising a curved body portion provided with an en larged head, one edge of which is adapted to act as a cutting edge. ,7 r

5.. A tool for undercutting the pin holes in center shells for insulators comprising a body and a tapered head, said head being curved in cross sectionand having a maximum separation of the edges approximately equal to the diameter of the pin hole to be undercut. n

6. A tool for undercutting the pin holes in center shells for, insulators comprising a body and a tapered head, one edgeof which is adapted to act as a cutting edge, said head being semicircular in cross section and having its maximum diameter at a point spaced from its free end-and approximately equal to the diameter of the pin hole to be undercut.

7. A tool for undercutting the pin holes of center shells for insulators comprising'a curved body portion provided with a. tapering head having one of its edges formed into a cutting edge and a rib extending within the head adjacent its other edge.

8. A tool for undercutting the pin holes I ing head having one of its edges formed into a cutting edge and a rib extending Within the head adjacent its other edge and Within the body.

9. In apparatus for undercutting the pinholes oi": center shells for insulators, in combination, a rotatable support for a center shell, a vertically and transversely movable tool support and a tool, comprising a curved body and an enlarged head one edge of which is adapted to act as a cutting edge, secured to said support.

10. In apparatus for undercutting the pin holes of center shells for insulators, in com 1 bination. a rotatable support for a center tool support and a tool, comprising a curved body and an enlarged head one edge of Which is adapted to act as a cutting edge,

secured to said tool support, said tool support being normally positioned so that the tool secured thereto will be supported substantially coaXi-ally with the pin hole in a center shell supported by said rotatable support.

In testimony of Which invention, I have hereunto set my hand, at Norristown, Pa., on this 21st day of December, 1926.

WVILLIAM HENRY SMITH. 

